AP05 - respiratory neurology

Question 1

What do the anterior rami of the thorax bridge into?

Answer 1

muscular branch
branches to parietal pleura
lateral cutaneous branch
intercostal nerve
anterior cutaneous branch

Question 2

How do carotid bodies detect CO2?

Answer 2

diffuses into cell, increaseing carbonic acid concentration, and hence protons

this reduces K+ content, depolarising the cell.

Ca2+ enters, and the glomus cells are excited, releasing neurotransmitter

Question 3

What other state would mimic the same effect of high CO2?

Answer 3

acidosis inhibits acid-base transporters, changing proton concentrations ultimately have the same effect

Question 4

What do chemoreceptors send messages to?

Answer 4

the medulla

Question 5

What might damage to T2-T5 cause?

Answer 5

inhibition of mucus secretion in the trachea

inhibits control of tracheal smooth muscle, bridging the gap between the free end of the C-chaped cartilages

Question 6

What is the carina of the trachea sensitive to?

Answer 6

light touch

Question 7

Where is the trachea carina?

Answer 7

base of trachea at the separation into left and right bronchi

Question 8

What is afferent pathway of the cough reflex?

Answer 8

sensory fibres in ciliated epithelium of upper airway and cardiac and oesophageal branches from diaphragm go to medulla via the Vagus nerve

Question 9

What is the central pathway of the cough reflex?

Answer 9

coordination centre for coughing in the Pons and medulla oblongata, likely to overlap with respiratory nuclei

initially in the solitary nucleus, and then others, like the pre-Botzinger complex

the caudal medullary raphe nuclei (obscurus and magnus) are essential

Question 10

What is the efferent pathway of the cough reflex?

Answer 10

to diaphragm via vagus, phrenic, and spinal motor nerves

to the intercostal muscles via phrenic and motor nerves

to the larynx from the nucleus ambiguus via laryngeal branches of the vagus nerve

Question 11

How can you identify vagal afferent terminations?

Answer 11

their conductance speed

A fibre >3m/s
C fibre <2m/s

Question 12

What is the structure of each neurovascular bundles for the ribs?

Answer 12

rib costal groove
vein
artery
nerve

Question 13

How would you test for intercostal nerve damage?

Answer 13

press intercostal area and take a deep breath, positive test with pain

Question 14

What might cause Phrenic nerve damage other than trauma?

Answer 14

up to 10% of cases are during operation, in heart or abdominal surgery

Question 15

What is the valsalva manourvre?

Answer 15

forcefull exhalation when the mouth and nose are shut, it can be used as a test of autonomic control of the heart

Question 16

What is the physiological response to the valsalva manouvre?

Answer 16

initial pressure rise

reduced nervous return and compensation

pressure release

return of cardiac output

Question 17

What accounts for the initial increase in pressure during the valsalva manouvre?

Answer 17

blood is forced from pulmonary circulation into the left atrium, causing a mild rise in stroke volume

Question 18

What accounts for the reduced venous return and compensation in the valsalva manouvre?

Answer 18

return of the venous blood to the heart is impeded by the pressure in the chest, heart output falls

Question 19

What accounts for the pressure release in the valsalva manouvre?

Answer 19

pulmonary vessels and aorta re-expand

venous blood can then enter the chest and heart, cardiac output begins to increase

Question 20

What might the valsalva manouvre be used to diagnose?

Answer 20

if with headache - arnold-chiari malformation

along with a echocardiogram it can be used to diagnose heart abnormalities (like in episodes of supraventrivular tachycardia)

Question 21

Name 3 causes of diaphragmatic paralysis

Answer 21

mechanical trauma
compression
neuropathies (such as from diabetes)

Question 22

What does diaphragmatic paralysis cause?

Answer 22

paradoxical movement, affected side moves upwards during inspiration

Question 23

How might a unilateral diaphragmatic paralysis present?

Answer 23

usually aymptomatic and is often found incidentally on CXR

Question 24

What is the pulmonary plexus and its’ relationship to the cardiac and oseophageal plexus?

Answer 24

it is the convergence of autonomic fibres supplying the lung

inferior to cardiac plexus
anteriorinferior to oesophageal plexus

Question 25

What does the pulmonary plexus receive innervation from?

Answer 25

left and right vagus nerves

sympathetics from rami of superior 4 thoracic ganglia

Question 26

What muscles are involved in quiet inspiration?

Answer 26

diaphragm
levatores
costarum
serratus posterior superior
external intercostals

Question 27

What muscles are involved in quiet expiration?

Answer 27

serratus posterior inferior
internal intercostals
diaphragm (passive recoil)